When it comes to turbocharged retrofits, the first thing most people think about is the pippie valve, which in a sense has become a symbol of the retrofit.
However, the car has never been modified to be "fancy". Many of the turbocharged models that have been modified with strong performance do not use the pressure relief valve with obvious sound, and professional cars also use the pressure relief valve with internal leakage.
In fact, "pressure relief valve" is a general name, the official name should be "bypass valve", in the turbocharging system of the car, including the inlet and outlet pressure relief valves, mainly because the turbocharger is divided into the inlet pressure shell and the exhaust pressure shell. The function of the former is to discharge the excess air from the inlet pipe when the throttle is closed, so as to prevent the backward air from colliding with the high-speed rotating inlet blade, thus causing damage to the inlet blade.
The latter is mainly used to protect the safety of the turbocharger and the engine itself, because the turbocharger is driven by the exhaust gas from the engine. High temperature, high pressure and high speed make it in a very bad working environment.
Among them, the supertemperature will cause damage to the supercharger blade with a speed of more than 100,000 revolutions per minute, and the engine oil will evaporate excessively at high temperature, reducing the lubrication ability of the blade axle center and sleeve (bearing). Overpressure can make the thrust bearing that supports and secures the blade shaft center and sleeve (bearing) too much pressure, and some turbocharger thrust bearing may be out of shape or break. At the same time, excess pressure over the normal range can also cause severe engine detonation, which is usually the main cause of engine damage.
The common turbocharger is equipped with a simple cylinder type exhaust pressure relief valve, and a preset pressure spring is installed inside the cylinder, which is connected by a connecting rod to the bypass valve of the supercharger outlet. When the exhaust pressure reaches the upper limit, the spring is completely compressed and the valve opens to control the pressure. This relatively simple exhaust pressure release valve known as physical, can also be called within the exhaust pressure relief valve discharge type. The main disadvantage is that it is too close to the exhaust pressure shell of the supercharger. High temperature will affect the stability of control pressure.
Therefore, some turbochargers with large size, high supercharging value or high performance are made of effluent exhaust pressure relief valve, which is called Wastegate. Its essence is still a spring-driven bypass valve. The difference is that Wastegate is installed on the branch pipe of the exhaust pipe.
Since it is mounted on a separate pipe, the working temperature of Wastegate is stable, and the stronger, more heat-resistant materials and structures make it more durable. Simple structures driven directly by exhaust pressure also greatly improve reliability. Many retrofit vehicles use the leakage vent pressure relief valve, can be replaced by different pressure springs and the installation of pressure controller for accurate pressure control, more suitable for high strength power modification.